#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <conio.h>
#include <ctype.h>
#include <time.h>

// `getch` is not available on linux. look for an alternative
#ifndef getch
    #define getch _getch
#endif

// Maximum guesses a player can take
#define MAXTRY 10
// Maximum letters a word may have
#define MAXLTR 128

const char * g_Words[] = {
    "house",
    "car",
    "phone",
    "brick",
    "moon",
    "elephant"
};

void ClearScreen()
{
#if defined(WIN32) || defined(_WIN32)
    system("cls");
#else
    system("clear");
#endif
}

const char * PickWord()
{
    // Generate a random index within the range of the words array
    const int i = rand() % (sizeof(g_Words) / sizeof(g_Words[0]));
    // Return the word located at the resulted index
    return g_Words[i];
}

void Render(const char * w, const char * l, int tries)
{
    printf("%3i tries left to guess the word: ", (MAXTRY - tries));
    // Keep an unaltered letter pointer
    const char * lb = l;
    // Output the guessed and hidden word letters
    while (*w != '\0' && (l - lb) < MAXLTR)
    {
        // Print the letter with a space to make it more distinguishable
        putchar(*l);
        putchar(' ');
        // Advance to the next character
        ++l;
        ++w;
    }
    // End the line
    puts("");
}

int main()
{
    // Feed the random generator with a seed
    // Use the generic current time-stamp
    srand(time(NULL));
    // Pick a random word to start with
    const char * word = PickWord();
    // Memory for the guessed words
    // Assuming they're bellow 128 characters
    char letters[MAXLTR];
    // Initialize all guessed characters to _
    memset(letters, '_', sizeof(letters));
    // Try counter and whether to pick a new word
    int tries = 0, renew = 0;
    // Perform the initial render
    Render(word, letters, tries);
    // Enter the application loop
    for(;;)
    {
        const char ch = tolower(getch());
        // Are we trying the game again?
        if (ch == '\r' /* <- ASCII for ENTER */ && renew > 0)
        {
            // Pick a new random word to start with
            // Note: doesn't check if the same word was picked!
            word = PickWord();
            // Initialize all guessed characters to underscore
            memset(letters, '_', sizeof(letters));
            // Reset the `try` counter
            tries = 0;
            // Game was renewed
            renew = 0;
            // Clear the screen
            ClearScreen();
            // Perform the initial render
            Render(word, letters, tries);
            // And start the game
            continue;
        }
        // Are we leaving the game?
        if (ch == 27 /* <- ASCII for ESC */)
        {
            // Clear the screen
            ClearScreen();
            // Show the answer only if the word wasn't guessed
            if (strncmp(word, letters, strlen(word)) == 0)
            {
                puts("Sad to see you go. And FYI, I let you win!");
            }
            else
            {
                printf("Sad to see you go. The word was: %s\n", word);
            }
            // Stop the game
            break;
        }
        // Is this an accepted letter? (isalnum(ch) alpha-numeric?)
        else if (isalpha(ch) == 0)
        {
            continue; // Invalid input
        }
        // Get pointers to the word and list of letters to compare
        char * l = letters;
        const char * w = word;
        // See if the given character is correct
        while (*w != '\0' && (l - letters) < MAXLTR)
        {
            // Was this letter already guessed?
            // And is this letter a match?
            if (*l == '_' && *w == ch)
            {
                // Unlock this letter
                *l = ch;
                // We're done here
                break;
            }
            // Advance to the next character
            ++l;
            ++w;
        }
        // Was there a match?
        if (*w == '\0' || (l - letters) >= MAXLTR)
        {
            ++tries; // Increment the number of tries
        }
        else
        {
            // tries = 0; // Reset the counter whenever the player guesses a letter?
        }
        // Did we exhaust the number of tries?
        if (tries >= MAXTRY)
        {
            // Clear the screen
            ClearScreen();
            // Ask the player if he wants to try again
            printf("GAME OVER! The word you were looking for was actually '%s'\n", word);
            puts("Press ENTER to try again or ESC to leave.");
            // Renew the game on next loop
            renew = 1;
            // Wait for input
            continue;
        }
        // Did the user completed guessing the word?
        else if (strncmp(word, letters, strlen(word)) == 0)
        {
            // Clear the screen
            ClearScreen();
            // Ask the player if he wants to try again
            printf("YOU WON! The word you were looking for was indeed '%s'\n", word);
            puts("Press ENTER to try again or ESC to leave.");
            // Renew the game on next loop
            renew = 1;
            // Wait for next input
            continue;
        }
        // Render everything to the screen again
        Render(word, letters, tries);
    };
}